Inductive fuze setters for projectiles are known in the art. Inductive fuze setters are used to transmit data to a projectile, such as time-of-flight data, time-to-burst data, target coordinates, etc., as is known in the art. It is very important to be able to quickly and reliably transmit data to a projectile as, for example, the projectile is moving from a magazine to a cannon. Moreover, it is important to be able to verify that the projectile has correctly received the transmitted data.
Typically, the projectile includes an internal coil for forming an inductive interface with an external setter device. The setter device includes a coil which, when placed in close proximity to the coil within the projectile, becomes inductively coupled to the projectile coil. The setter coil is excited and modulated to communicate data to the projectile. The projectile coil receives the data which can then be provided to appropriate electronic circuitry included within the projectile as is known. Conversely, the electronic circuitry within the projectile may excite and modulate the projectile coil and thereby inductively transmit data to the setter coil.
In order to improve inductive coupling between the setter coil and projectile coil, it has been known include a magnetic core within the projectile. The projectile coil is wound around the magnetic core in order to concentrate the magnetic flux and increase coupling. The magnetic core may be made of iron or typical ferrite core material. However, iron is relatively heavy and can thereby detract from the projectile capacity. Typical ferrite core material, on the other hand, may be slightly lighter in weight compared to iron. However, ferrite core material is typically very brittle, not easily machinable, and subject to cracking and/or otherwise losing its structural integrity during handling and/or use of the projectile. This can compromise the inductive coupling achievable with the setter coil, as well as possibly affect the aerodynamic or other characteristics of the projectile during or following launch. Furthermore, the shape of the magnetic core is oftentimes atypical due to space constraints, etc., within the projectile. As a result, machining of an iron or ferrite core can be both time consuming and expensive.
Also in the past, it has been known to include a separate set of coils, one in the setter device and one in the projectile, to provide power to the circuitry included within the projectile. This presented problems in that more volume was taken up within the projectile, and care was required to avoid coupling between the power coil and the data coil. Alternatively, power was provided within the projectile via a battery. However, battery life was limited and the cost of batteries contributed significantly to the cost of the projectile. There have been attempts to provide power and data to a projectile via a common coupling. (See, e.g., U.S. Pat. No. 4,644,864). However, such attempts met with only limited success.
In view of the aforementioned shortcomings associated with conventional inductive setters, there is a strong need in the art for an inductive interface which does not contribute significantly to the weight or cost of a projectile. Moreover, there is a strong need in the art for an inductive interface which is easily machinable and not likely to crack or otherwise lose its structural integrity prior to detonation. In addition, there is a strong need in the art for an improved way of communicating power and data between the setter device and projectile.